Ammunition



Patented Apr. 14, 1925.

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naar Vries HELMUT-I PAUL TJARTIN AND OVJEN DAVE@ LUCAS, GFVJESTIVINSTER, VVLONDON, ENG- LAND, ASSIGNORS TO LAND.

L. EXPERIMENTAL LIMITEE, E' VVESTMNSTER, ENG'- AMMUNITION.

Original application filed. September 8, 1920, Serial No. 4055,056.Divided and this application tiled October 14, 1922.

vide an improved form of primer or detonator for this purpose.

ln the accompanying drawings Figure 1 is a section drawn to a largerYscale of a cap adapted for use when it is desired to lire the cartridgewith a hot wire.

Figure 2 is a view similar to Figure 1 showing a modified form of thecap. A

Figure V3 is a, diagrammatic end view shewing a position of vthe hotwire bridger Figure i is a plan shewing another position of the hot wirebridge.

A hole 2 is provided in the base 3 of the ordinary copper cap L1. A discof paper 5 with a small central hole 6 has the filament 7 attached to itin such a way that it is stretched across the face of the paper, the twoends 8 8 being fastened diametrically opposite on its under side; thepaper may have heen previously impregnated with shellac, paratlin wax,or other suitable insulating' and water-proof material. rlhis dise isthen dropped in position with the ends of the filament downwards insidethe cap. A small copper disc 9 of diameter less than that oi" the capwithA a small central hole is then placed over the cap l on the outside,another disc ot impregnated paper 10 being interposed between it and thecap. The whole is then riveted together by a suitable rivet 11 on theoutside of the cap and with a head 12 pressing on the centre oit thelament above the paper K dise on the inside7 thus formingthe central ythe cap.

It will be seen that by this method two paths are provided for thecurrent from the Serial No. 594,454v

is recessed at the base so as to leave an p annular trough inside 'thecap in which the German silver wire lies described below. A hole 2 ispunched centrally in the base 3 ofthe copper cap t.' A mica disc 5d alsoprovided with a central hole but of smaller diameter than that in thecapi is placed inside the cap. A` ring 13 of German silver or othersuitable material, is formed to maire a. spring iitwhen pressed into theinside of the cap. A wire 7 of tungsten of diameter about .0015 inchesor ot platinum silver of about .0025 inches is stretched across the topoi the cap and the spring:r ring 13 is then pressed down, carrying thewire with it, the ends of which arel then cut off iiush. AThis leavesthe Wire stretched centrally across the base of the cap, and resting onthetop of the mica disc 5, Another mica disc 10il with a similaicentralhole is then titte-d on the outside vof the cap over the rivet. A copperwasher 9 oi smaller diameter than the mica, with central hole is placedon the top et the'mica washer 10a; a small rivet 1l is now droppedthrough the hole in the cap with the head of the rivet (which isflattened) inside the cap7 and in such a way that the fine wireA liesunder the rivet head` 'and the whole riveted together. It will be seenthat as the mica disc-5"L inside the cap has a hole smaller than t'iatin the base of the copper cap 4, the rivet 11 is prevented from touchingthe copper eap el, being held centrally by the mica disc 5". The copperwasher 9 at the back of the cap forms the insulated contact to thecentre of the line wire 7, from which `point the current travelsradially through the two halves of the wire to the German silver ring13, the bodyot the copper cap and thus to the cartridge.

Instead of inca we may employ any other thin insulating material and weinay'employ other suitable material for the detonating wire instead oftungsten or platinum silver, such as platinum iridium and the like, theobject being to obtain a wire ot such diameter thatfwith the voltageapplied it shall be heated to ashigli'a temperature as possible in theshortest tiine, say about given about d volts Will operate the, cap,

but We use 8 yolts-bypreiierence.

The copper-rivet may have providedon either'side tivo projectionsWliicliare turned up at right angles to the shaft ofthe rivet,

When the latter is riveted in position, Vthe Wire is then dropped overthe head or the rivet instead of under i and the projections areApressed down inwards across the head of tlierivet and or the topv ofthe Wire,'tlius making a secure lContact with the rivet head.

The German silver spring ring may have two barb-s cut dianzetricallyopposite'one another, lunder which vthe `Wire is placed, the barbs beingthen pressed down, thus gripping the Wire and holding it securely; thering before beingiitted to the cap has a. gap

Whichis taken up when the` ring is pressedV into'the cap, thus causingthe tungsten wire to become slack.

,Vile harefound that a suitable lilament is one either or' tungsten orplatinum silier, and

a suitable Ythickness niay'vary between .O05

an'dxOOQ inches diameter; the object ot this tine filament is thatavsliortlength of it is heated as instantaneously as possible by the ypassage ot 'the current to such a high teur perature that it isvolatilized, the action in detoiiatiiig the" tulininate vbeing thus ei;-ti'emely rapid. Y

That We `claiin and desire to secure Vby Letters Patent of the UnitedStates is 1. For use in a cart-ridge, an electrically ignited primercomprising in combination a metal cap, a Washer o insulating materialinserted from the front end of the cana ContactY element passing throughsaid washer and throughthe base ot said cap out of contact With saidbase and a Wire which passes over the front surface of said Washer andis electrically connected at one point to said contact element andatanother point to said cap 2. For use ina cartridge, an electricallyignited primer comprising in combination a inetal cap. a Washer otinsulating material inserted 'troni thei'ront end oit the cap, and

arranged With Vits rear surface in contact.

with the base of said cap,a contact element passing throughY said Washerand through thebase'of said cap out of contact With said base and a Wirewhich passes over the liront surface oi saidwasher and is electricallyconnected at one point to said contact element and at another point tosaid cap. o

3. For use in a cartridge, an electrically. iguitedrprimer comprising incombina-tion nietal cap, a Washer ot insulating material inserted fromthe front end of the cap, a contact element passing through said Washer1 and through the base of said cap out of con- 5000*.- oit al second. iVile find that With the wire" 1 vvover, the iront surface of said Washerand tact- With said base and servingto fasten the Washer.to-saidrbasefand a Wire which passes is electrically connected at onepoint to said contacteleinent and at another point to said cap. Y

4t. use in a. cartridge, an electrically ignited primer comprisingiiicombination a metal fcap, a Wasliery-of. insulating inaterialainserted troni-the front end of the cap, a conta element in the torni ota rivet passing .through said washer and'vthroughthe base ot said capout oit' contact With-saidbase rserif'ingi; to tasten theywasher tosaid-base,

antL a wire `which passes'over the front surf 'tace of said 1Washer and.is electrically connectedk atcne vpoint to said; contact elementContact yelement 'inthefforni oia riiet'pasming through said Washer andrthrough the baseo'f said capfout of' contactwwith saidr base andserving'to fasten tlie'washer to said base. and -a Wire Whichpasses overthe iront .surface ot vsaid"ivasher'and vis elec--V trically connectedatits iniddle'to said contact element and at its endsvto'said cap.-

ifor ruse in a. cartridge, electrically ign itedY primer comprising :incombination a metal cap.ga contact passing throughjthe base ci said cap,-nieans lforinsulating said Contact fromf-thebase, these means includinga -non-conducting` Washer* arranged in contact with the inner surface:ofY the base,-

a wire one part of Which is electrically connectedtozsaid contact,A andadevice iitting in an annular recess in thebase Voi." said: cap andholding :another .pa-rt ot'sa'id Wire'inv con-tact with said base;`theportion or" the Wire be-l tii'een said parts being yinsulated fromthe baseby said Washer. i 7. ,For use inr a cartridgeA anelectricallyllO,`

igiiitedprii'ncr comprising in combination a nietal cap, a contactpassing through the base ot said cap. means for insulzine` said ContactJfrom .tlie.base. theseineans including a non-conducting Washer arrangedin contact o with the inner surtaceof the lia-sc al Wireonel partotiifhich: is electrically connected to said contact, and a spring ringlitt-ing in an annular recess iiiA thebase ot' said cap and, i holdinganotherwpart of said Wire in contact with said base, the por-tion of thewire betweensaidlv parts being insulated from Vthe base by saidWasliei".;.

l-lELldUTI-I PAUL MARTIN. QUIEN DAVID LUCAS.

